This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Helicobacter pylori causes an inflammatory infiltrate in gastric mucosa that in about 10% of cases progresses to peptic ulcer disease or gastric cancer. Disease results from an interaction between strain-specific bacterial virulence genes and the particular host response, neither of which is well understood. Since experimental inoculation of rhesus macaques with H. pylori causes gastritis that closely mimics human infection, this model provides a unique opportunity to further our understanding of H. pylori pathogenesis.